SharpDX.Toolkit, a high level XNA like API for Direct3D11 is under heavy development. The toolkit is not yet part of the distribution but a Beta version should be released by the end of October. Currently implemented:

A full HLSL Effect / FX system, very similar to legacy FX system, using efficiently Direct3D11, compatible with Windows Desktop and Windows 8 Modern, with a custom compilers. All XNA stock effects (BasicEffect, DualTextureEffect...etc.) were successfully ported to it. The toolkit is coming with its own effect compiler (tkfxc) similar to standard fxc.exe.

Concerning support for Windows Phone 8 (WP8) nothing to announce yet until the official release of the WP8 SDK.

...

And when they say "*Lots* of small enhancements, changes, bug fixes" they really mean it...!

And there's even more for Win7/8 Desktop app's! Here's the VS 2010 Sample Solution

"Wait, what's the big picture? What is SharpDX again?"

The power of DirectX for .Net

SharpDX is an open-source project delivering the full DirectX API under the .Net platform, allowing the development of high performance game, 2D and 3D graphics rendering as well as realtime sound application.

SharpDX is built with a custom tool called SharpGen able to generate automatically a .NET API directly from the DirectX SDK headers, thus allowing a tight mapping with the native API while taking advantages of the great strength of the .Net ecosystem. SharpDX is fully supporting all Windows platforms including latest Windows 8 Metro. Easily develop multimedia applications for desktop and metro with the same API!